Leitz Valoy II - shortnecked bulbs, replacements?

I've always wanted one of these enlargers, so I am toying with the idea again.

Apart from the normal adventure of trying to get E27 incandescent enlarger bulbs, it seems that they use a "shortnecked bulb" - what does that mean really? Would a Philips PF603 work? What about other light sources, anything useable there?

I've seen the PH211 being mentioned as useable for the Valoy, but I don't know if it is available in 220 volts. The closest I seem to be able to get is the Philips PF603. Let's see if anyone else chimes in.